Glossary

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Application: A computer program used to accomplish specific tasks not related to the computer itself (e.g., word processors, spreadsheets, accounting systems).

Asynchronous Transfer Mode (ATM): ATM is the name given to a network technology based on transferring data in cells or packets of a fixed size. The cell used with ATM is relatively small compared to units used with older technologies. The small, constant cell size allows ATM equipment to transmit video, audio, and computer data over the same network, while ensuring that no single type of data dominates the line.

ATM: See Asynchronous Transfer Mode.

AUP: See Acceptable Use Policy.

Bandwidth: The amount of data that can be moved to a computer a given period of time.

Banner Advertisement: A typically rectangular advertisement on a web site placed above, below, or on the sides of the sites main content and linked to the advertiser's own web site.

Browser: A software application used to locate and display web pages. The two most popular web browsers are Netscape™ and Microsoft Internet Explorer™ . Both are graphical browsers, meaning they can display graphics as well as text. In addition, most modern browsers can present multimedia information, including sound and video, though they require plug-ins (q.v.) for some formats.

Cable Modem: A modem (q.v.) designed to operate over cable-TV lines rather than phone lines.

Cellular Wireless: A method of connection to the Internet that does not use any ground lines. The existing standard protocol is relatively slow; however, newer standards are evolving. Care must be taken to secure these networks from hackers who can literally pull information out of the air.

Central Processing Unit (CPU): The brain of the computer. Two components found in the CPU are the arithmetic logic unit, which performs calculations and logical operations, and the control unit, which decodes and executes instructions.

CPU: See Central Processing Unit.

Dial-Up Services: A dial-up service is a method of connection to the Internet through a modem and a traditional telephone line. Dial-up services are usually sufficient for using the web and e-mail applications, but are not as effective for transferring larger files (e.g., video clips).

Digital Subscriber Line (DSL): A high-bandwidth technology for connecting to the Internet using the copper telephone lines that exist in almost every home and office. Special hardware attached to both ends of the line allows data transmission at far greater speeds than standard telephone wiring and dial-up connectivity.

Domain Name: Used in URLs to identify particular web pages or sites located on the Internet. For example, the domain name nces.ed.gov represents the web site for the National Center for Education Statistics.

DSL: See Digital Subscriber Line.

Dumb Terminal: A dumb terminal is a "computer unit" that has a monitor and a keyboard that must connect to another computer for processing power.

File Transfer Protocol (FTP): A standard Internet protocol for transferring files from one computer to another.

Filtering: Filtering is the process of controlling access to a network by analyzing the incoming and outgoing packets. A filter lets the packets pass, or not pass, based on the IP addresses of the source and/or destination. E-mail messages and web sites can also be filtered based on content.

Firewall: An electronic boundary (or physical piece of hardware) that prevents unauthorized users and/or packets of data or information (e.g., files and programs) from accessing a protected system.

Fixed Wireless: These "computers" are wireless devices or systems that are in fixed locations, such as an office or home, as opposed to devices that are mobile, such as cell phones or personal data assistants (PDAs).

Frame Relay: A packet-switching protocol for connecting devices on a Wide Area Network (WAN). Frame relay networks in the United States support data transfer rates at T-1 (1.544 Mbps) and T-3 (45 Mbps) speeds. Most telephone companies now provide frame relay service for customers who want connections from 56 Kbps to T-1 speeds.

Frames: A feature supported by most modern web browsers than enables the web site author to divide the browser display area into two or more sections (frames). The contents of each frame are taken from a different web page. Frames provide great flexibility in designing web pages, but many designers avoid them because current browsers support them unevenly.

FTP: See File Transfer Protocol.

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Host: (n) A computer system that is accessed by a user from a remote location. Typically, the term is used when there are two computer systems connected by modems and telephone lines. The system that contains the data is called the host, while the computer at which the user sits is called the remote terminal.

(v) To host is to provide the infrastructure for a computer service. For example, a company that hosts web servers may provide the content on the server (e.g., web site or other content), but another company may control communications lines required by the server.

HTML: See Hypertext Markup Language.

Hypertext Markup Language (HTML): A formatting language used to create web pages and specify how a page will appear on screen.

Integrated Services Digital Network (ISDN): An ISDN line is a digital phone line that can transmit data, video, and voice. (ISDN lines are "point-to-point" connections from the telephone company to the computer user.)

Internet Service Provider (ISP): An ISP is an entity that provides commercial access to the Internet. Service can range in size from dial-up access with a 56-Kbps ordinary telephone line and several dozens of customers to multiple pops (i.e., connection points) in multiple cities with substantial backbones and thousands, tens of thousands, or more customers. ISPs may also provide web hosting and other services.

IP Address: An IP address is an identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages according to the destination IP address. Within a private network, IP addresses can be assigned at random as long as each one is unique. However, connecting a private network to the Internet requires using publicly registered IP addresses (called Internet addresses) to avoid duplicates.

ISDN: See Integrated Services Digital Network.

Intranet: An intranet is a private, internal network that provides users access to applications within the agency.

ISP: See Internet Service Provider.

LAN: See Local Area Network.

Local Area Network (LAN): A linkage of computers and/or peripherals (e.g., printer) confined to a limited area that may consist of a room, building, or campus that allows users to communicate and share information.

List Server: A list server is a device that operates mailing lists and distributes new messages, newsletters, or other postings from list members to the entire list's subscribers. Postings can be delivered as they are received or they can be digested and delivered on a scheduled basis.

Meta Tag: A command inserted in a document that specifies how the document, or a portion of the document, should be formatted. Tags are used by all format specifications that store documents as text files.

Modem: A modem is a contraction of "modulator/demodulator." It is a device that connects the computer to a telephone line (or, perhaps, another wire) for communication with another remote computer or information network. Modems may be internal or external to the computer case. Modems are classified according to the speed with which they send and receive information.

Needs Assessment: A "needs assessment" is a process for determining the desired functions for computer and networking technology and/or determining the needs this technology will meet.

Network: A group of computers connected to each other to share computer software, data, communications, and peripheral devices. Commonly, the definition of a network includes the hardware and software needed to connect the computers together.

Node: In a discussion of networks, a "node" refers to a processing location. A node can be a computer or some other device, such as a printer. Every node has a unique network address.

Operating System: The operating system (OS) contains the electronic instructions that control the computer and run the programs. This software is generally specific to a type of computer (e.g., Windows 2000, UNIX Linux, and Mac OS X).

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Packet: A packet is a message fragment containing data or information. When messages are sent on the Internet, they are broken into smaller, more easily transportable pieces called packets. Each packet consists of a header and a piece of the message. A single e-mail message may actually be broken into a half-dozen different packets.

Packet Sniffing: Packet sniffing refers to the collection and analysis of data packets (including contents) as they transit the network.

Packet Switching: Refers to the protocols within a network that determine how messages are broken into packets (q.v.) and routed to their destinations.

PDA: See Personal Data Assistant.

PDF: See Portable Document Format.

Peer-to-Peer Network (P2P): A configuration in which each computer on the network has the same capabilities as the other computers on the network and any one of them can initiate a communications session with another. Any peer can add files, copy them, and move them to any peer computer on the network (where people store their files on their own computers). Therefore, any person on the network can access those files, copy them, and move the copies over the network to another computer.

Personal Data Assistant (PDA): A PDA is a handheld device (e.g. Palm Pilot®, PocketPC®, etc.) that may combine many computing activities. PDAs that are more powerful may function as cellular phones, fax transmitters, web browsers, and personal organizers.

Plug-Ins: Plug-Ins are software pieces that add a specific feature or service to a larger system. For example, in order to view a PDF file, the Adobe Acrobat Reader® plug-in is required.

Pop-Up Ads: Advertisements that appear in a separate browser window while a web site is being viewed.

Portable Document Format (PDF): A file format developed by Adobe Systems® that captures formatting information from a variety of desktop publishing applications, making it possible to send formatted documents and have them appear on the recipient's monitor or printer as they were intended. To view a file in PDF format, a free copy of Adobe Acrobat Reader® can be downloaded from Adobe Systems at www.adobe.com.

Portal: (Also, web portal.) "Portal" refers to a web site or service that offers a broad array of resources and services, such as e-mail, forums, search engines, and online shopping malls. The first web portals were online services, such as AOL, which provided access to the web; now most of the traditional search engines (e.g. Yahoo®, Google®, etc.) are web portals, modified to attract and keep a larger audience.

P2P: See Peer-to-Peer Network.

RAM: See Random Access Memory.

Random Access Memory (RAM): The place in the computer where the operating system, applications programs, and data in current use are kept temporarily. When the computer is turned off, the data are removed from RAM and either stored elsewhere in the computer or deleted.

Read-Write Drive: A read-write drive is a device that enables a computer to read or write data, ranging from a simple floppy disk drive to a complex drive, which through laser technology writes data on a compact disk (CD) or a digital versatile disk (DVD).

Router: The device or software that determines the next network point to which a packet (q.v.) will be forwarded. The packet travels from point to point along the network until it arrives at its destination.

Server: A server is a computer or device on a network that manages network resources. For example, a file server is a computer and storage device dedicated to storing files. Any user on the network can store files on the file server. A print server is a computer system that manages one or more printers, a network server manages network traffic, and a database server processes database queries. It is possible to partition the space on one computer to create more than one server.

Source Code: Source code is instructions to the computer in their original form. Initially, a programmer writes a program in a particular programming language called the source code. To execute the program, the programmer must translate the code into "machine language," the only language a computer understands. Source code is the only format readable by humans.

Spam: Spam refers to electronic junk mail or junk newsgroup postings. Some people define spam even more generally as any unsolicited e-mail. In addition to being a nuisance, spam also eats up a lot of network bandwidth. Because the Internet is a public network, little can be done to prevent spam, just as it is impossible to prevent junk mail. However, the use of software filters in e-mail programs can be used to remove most spam sent through e-mail.

Style Sheets: Templates for web page design that can be built into the programming of a site to provide continuity in appearance and layout across the various pages.

Surfing: To "surf" is to move from site to site on the Internet in a random or questing way while searching for topics of interest.

TCP/IP: Refers to communication protocols used to connect hosts on the Internet. TCP stands for Transmission Control Protocol, which is the main protocol in an IP (Internet Protocol) network. Whereas the IP deals solely with packet switching, TCP/IP allow two hosts to communicate with long streams of data at one time, thus always guaranteeing the packets arrive in the correct order.

Thin Client: A network computer without a hard disk drive, which, in client/server applications, is designed to be especially small so that the bulk of the data processing occurs on the server.

Universal Resource Locator (URL): A World Wide Web address composed of several parts including the protocol, the server where the "resource" (e.g., web page) resides, the path, and the file name of the resource. An example of a URL is http://nces.ed.gov.

URL: See Uniform Resource Locator.

W3C: See World Wide Web Consortium.

WAN: See Wide Area Network.

Web Portal: See Portal.

Wide Area Network (WAN): A data communications linkage (e.g., dedicated line, radio waves) that allows users to communicate and share information over distances greater than the distance transmitted by local area networks (e.g., building to building). The Internet is an example of a WAN.

World Wide Web Consortium (W3C): W3C is a forum for information, commerce, and collective action by a consortium of respected web inventors and developers who seek to develop technologies to enhance use of the World Wide Web (http://www.w3.org/). Tim Berners-Lee, the original architect of the World Wide Web, founded W3C in 1994.